R/calibrateSeries.R

In xRing: Identify and Measure Tree Rings on X-Ray Micro-Density Profiles

calibrateSeries <- function(profile, thickness, calibration) {
  if (NCOL(profile) == 2) {
    profile <- profile[, 2]
  }
  if (is.list(calibration)) {
    calibration <- loess(calibration$y ~ calibration$x)
  }
  profile <-
    pmax(pmin(profile, max(calibration$x)), min(calibration$x))
  optical_density <- predict(calibration, newdata = profile)
  if (is.list(optical_density)) {
    optical_density <- optical_density$y
  }
  density <- optical_density / thickness
  density
}